Time blocking for days that don’t go to plan

Time blocking means giving each task its own slot on your calendar, so the plan says when as well as what. A blocked day holds up better with room to change: a few fixed anchors, flexible blocks between them, buffers, and simple rules for what to do when a block runs over.

What is time blocking?

Time blocking is planning your day as a set of slots on the calendar, each with one task or one kind of work, a start and an end. A to-do list says what needs doing. A blocked calendar also says when, and shows whether it all fits.

Blocks come in a few kinds:

• Fixed anchors. Things that can’t move, such as meetings, a school run or an appointment.
• Task blocks. One task, or a batch of similar small ones, like “draft the report” or “invoices and email”.
• Buffers. Empty slots that absorb overruns and surprises.
• Breaks. Lunch, a walk, time away from the screen.

A related method, timeboxing, gives a task a fixed amount of time and stops when it runs out. The two often go together: the block says when, and the box says how long the task gets.

Does time blocking work?

We found no controlled trial of time blocking on its own. The closest evidence comes from research on time management in general, which includes planning when you’ll do things, and it finds moderate links to performance and somewhat stronger links to wellbeing.

A correlation of 0.26 is a real but modest link: people who manage their time well tend to do somewhat better, with plenty of overlap between groups. The “adapt” part of that definition is the one a rigid blocked day leaves out.

There’s one more relevant line of research. Deciding in advance when and where you’ll do something, in an if-then form, had a medium-to-large effect on reaching goals across 94 tests. The same meta-analysis found these plans also helped people let go of a course of action that wasn’t working.² A time block is a when-and-where plan by another name, though those studies didn’t test calendars.

Why do time-blocked days fall apart?

Mostly because plans run long. People tend to estimate from the ideal version of a task, at least in studies with psychology students and often academic tasks, so a day blocked from those estimates is already full before the first surprise arrives.³

Three things make a blocked day fragile:

1. No slack. If every slot is full, one overrun pushes everything after it.
2. Blocks sized for the best case. Each block assumes the smooth version of its task.
3. No rule for an overrun. When a block runs long, you end up re-planning the whole day in your head while trying to work.

For more on why estimates come out short, see why tasks take longer than you think.

How do you keep a time-blocked day flexible?

Fix only what really can’t move, let the rest follow one another, and leave buffers where overruns usually happen. Then size each block from what that kind of task really takes you.

Anchors first. Put the true fixed points in first: meetings, pick-ups, appointments, and meals if they’re shared. Everything else is flexible.

Chain the flexible blocks. Order the rest as a sequence, “after the call, the invoices”, so that when one runs over, the next simply starts later. Only the anchors keep their times.

Leave buffers. Put a short empty slot after anything that tends to run long and before each fixed anchor. Let your own record decide how long they should be.

Size blocks from your own record. For one week, write down your guess for each block and the time it really took. The gap between the two is your personal buffer rule. In the 1994 planning studies, students who connected memories of similar past tasks to a new one before predicting stopped guessing short on average, though the authors noted that this didn’t yet show more accurate individual guesses.³

Block fewer hours than you have. A day blocked to the minute leaves no room for the day you’ll actually get. One option is to block only the morning, or only the hours that are yours to plan.

What should you do when a time block runs over?

Pick one of three moves, decided in advance: move it, shrink it or drop it. Then change only the next block or two, and leave the rest of the day alone.

Mark blocks when you plan. Next to each flexible block, write M, S or D for the move you’d make if the day goes wrong. Then an overrun only needs a glance at the letter, with nothing to work out.

Write the rule as an if-then plan. “If a block runs 15 minutes over, I shrink the next flexible block.” That’s the format with the strongest evidence in this article.

Change only the next block or two. Rebuilding the whole afternoon at 11:00 costs time and attention, and the afternoon may change again anyway. For shrinking a block to its smallest useful version, a routine that survives bad days walks through floor versions step by step.

Time blocking, timeboxing or a to-do list?

Each answers a different question: a to-do list says what, time blocking says when, and timeboxing says how long a task gets. You can combine them: a short list for the day, a few blocks for work that needs protected time, and a box on the task that tends to sprawl.

If the list itself feels heavy, see a to-do list that doesn’t overwhelm you.

Should you time block in your calendar app?

You can, and seeing blocks beside your meetings shows how much free time you really have. A few choices make it work better:

• Keep blocks on their own calendar. Most calendar apps let you add a second calendar that you can show or hide. Blocks kept there are easy to move and easy to tell apart from meetings.
• Decide what others see. In a shared work calendar, a block can show you as busy or as free. Busy protects the time; free leaves it open to colleagues.
• Leave part of the day unblocked. Then the calendar still shows real free time.
• Paper works too. A printed day grid and a kitchen timer do the same job, and moving a block is a quick arrow.

What does a re-planned day look like?

Here is an example day, planned in the morning and re-planned twice, with only the next block or two changed each time. Sam, our example, works from home and has a school pick-up at 15:15.

At 09:40 a colleague needs figures for a client by 11:00. Pulling them together takes 50 minutes. Sam looks at the letters and makes two changes.

At 14:15 the client slides need 20 more minutes. The afternoon buffer takes 15 of them, and the admin block marked D goes back on the list with no slot. Sam leaves for the pick-up on time.

Three small changes, each made in seconds because the letters were already on the plan. The afternoon was never rebuilt.

Questions people ask

Sources

1. Aeon, B., Faber, A., & Panaccio, A. (2021). Does time management work? A meta-analysis. PLOS ONE, 16(1), e0245066.META-ANALYSIS · NON-CLINICAL SAMPLES, WORK AND SCHOOL · 158 STUDIES, N = 53,957doi.org/10.1371/journal.pone.0245066↩ a
2. Gollwitzer, P. M., & Sheeran, P. (2006). Implementation intentions and goal achievement: A meta-analysis of effects and processes. Advances in Experimental Social Psychology, 38, 69–119.META-ANALYSIS · MIXED SAMPLES · 94 INDEPENDENT TESTSdoi.org/10.1016/S0065-2601(06)38002-1↩ a
3. Buehler, R., Griffin, D., & Ross, M. (1994). Exploring the “planning fallacy”: Why people underestimate their task completion times. Journal of Personality and Social Psychology, 67(3), 366–381.EXPERIMENTS · PSYCHOLOGY STUDENTS · 5 STUDIES (STUDY 1: N = 37)doi.org/10.1037/0022-3514.67.3.366↩ a b